window.onload = function(){  
    var t1 = new Tab("div1");  
    t1.init();  
}  
  
function Tab(id){  
    this.oParent = document.getElementById(id);  
    this.aInput = this.oParent.getElementsByTagName("input");  
    this.aDiv = this.oParent.getElementsByTagName("div");  
    this.iNow = 0;  
}  
  
Tab.prototype.init = function(){  
    var This = this;  
    for(var i=0; i<this.aInput.length;i++){  
        this.aInput[i].index = i;  
        this.aInput[i].onclick=function(){  
            This.change(this);  
        }  
    }     
}  
  
Tab.prototype.change = function(obj){  
    for(var i=0; i<this.aInput.length;i++){  
        this.aInput[i].className="";  
        this.aDiv[i].style.display="none";  
    }  
    obj.className="active";  
    this.aDiv[obj.index].style.display="block";  
}  
  